This is an anti-quackery and pro-neurodiversity blog. Most posts here have to do with the author's view that autism is not a new man-made phenomenon, but instead a natural part of our species that has always been with us, and should continue to be. Reasonable corrections and rebuttals are welcome and encouraged.

Monday, April 06, 2009

One Handley Turd I Left Out

In my previous post I looked at a few statements JB Handley made during his recent appearance on Larry King Live. Whether the statements were dishonest or simply wrong, I can't tell, but they were notable in their wrongness. They have even been referred to as fractally wrong.

I left an important one out, which I was pretty sure was wrong, but I needed to research it a bit more.

So I would tell you either go back to the 1989 schedule before this whole mess happened or go to Finland's schedule, Sweden's schedule, Norway's schedule and use theirs. Because their autism rates are one tenth of ours.

He must mean their rates of identified autism are one tenth of what they are in the US. I don't like it when people don't make that clarification.

But let's see what a quick search of the literature has to say.

Sweden

One study in the town of Karlstad, Sweden (Kadesjö et al. 1999) had found the prevalence among 7 year olds to be 1.21%. I'll let Lorna Wing summarize why this study is of interest:

Kadesjö et al (1999) report a study in Karlstad, a Swedish town. Although this was small scale it was very intensive (over 50% of the 7 year old children seen and assessed personally by the first author). The study found a prevalence for all autistic spectrum disorders for all levels of IQ, of 1.21%!!! Children were followed up four years later and had the diagnoses confirmed.

That's not all, though. You have, for example, Arvidsson et al. (1997), a study that set out to identify "all individuals with severe degrees of autistic behaviour." They found a prevalence of 31 in 10,000 among 3 to 6 year olds. This is more like half of the consensus prevalence in the US.

Then there is Gillberg et al. (2006) which finds a prevalence of 20.9 in 10,000 for autistic disorder, and 32.9 in 10,000 for "other ASDs." That's 53.8 in 10,000 total.

There are several other studies from Sweden we could look at, but I think the wrongness of Handley's claim has been clearly established just with the ones mentioned.

Finland

Mattila et al. (2007) found a prevalence of 25 in 10,000 for Asperger's Syndrome alone. This is actually higher than what the prevalence of Asperger's in children is normally found to be.

An older study, Kielinen et al. (2000), finds a prevalence of 20.7 in 10,000 among 5 to 7 year olds. This is lower than the US consensus prevalence, but it's only 1/3rd of it, not 1/10th. Additionally, note that 50% of the children had IQs below 70. This is different to what you see in California DDS, for example.

Norway

The most recent epidemiology from Norway is a bit old, and here we do see that the prevalence is similar to what it traditionally was for Kanner autism. For example, Sponheim & Skjeldal (1998) find a prevalence of 4 to 5 in 10,000 for 3 to 14 year olds, using ICD-10 criteria.

However, there's a recent screening of 7 to 9 year old children using the ASSQ. That's Posserud et al. (2006). It finds that 2.1% of children were high scorers in the ASSQ when both teacher and parent questionnaires were considered. (It was 2.7% if they considered teacher forms only, as some parents declined to participate.) That seems high.

Unfortunately, Posserud et al. don't tell us how many were confirmed to be diagnosable with ASD after the screening. There's an update of that study, Posserud et al. (2009). I wish I had a copy. All I know is that the ASSQ is found to have a sensitivity of 0.91 and specificity of 0.86, which appears good.

In any case, JB Handley's assumption is kind of simplistic even if we only consider the country of Norway, as it ignores all the issues involved in identifying autism.

9 comments:

JB isn't interested in finding out what the facts of autism are - he has already determined what the facts are and is trying to sell them to the general public.

As long as we see this as a scientific debate, we will always be playing "catch up". The JB Handleys are not constrained by a desire to be accurate nor are they reluctant to distort data or even use outright falsehoods if it will sell their "product".

That "product" - for those who haven't figured it out yet - is the "Too many, too soon" idea (previously known as the "Autism is mercury poisoning" brand). JB isn't interested in hearing about data or how his methodology is incorrect or his claims aren't supported - he's already decided what the "facts" are and he's only interested in selling his version - "Too many, too soon."

Prometheus is right, we are always playing "catch-up". It's an age-old public relations skill–the first statement is always the one that sets the debate. The Republicans used that technique well with the whole Swift Boat issue with John Kerry.

Unfortunately, since we use science and rational discourse to develop theories, it's difficult to take the lead. In 1995, no one was studying autism and vaccines, because there was no link between the two. Then Wakefield's lies became public, and it's been catch up ever since. If we could predict the future (yes, we will have to suspend science for a moment), one of us would have published a huge article on how safe vaccines are, wrote a book about the all of the cute children growing up without measles, mumps, rubella, polio (you get the point), and how they were doing so well in school. Being a PR ploy exclusively, we find a beautiful actress who's child received all of the vaccines, and had her promote her new book: Vaccines and how they allowed my children to grow up.

But see, we can't predict what the next alternative medicine woo is going to hit the national consciousness. Sad.

Norway: We found that the ASSQ had good screening properties forall ASD in a total population sample. Using the combinedcriteria of parent and/or teacher ASSQ score above cut-offgave the optimal screening properties of both high sensitivityand high specificity. We found that more than 90% ofthe children (21 out of 23) who received a diagnosis ofautism or broader autism phenotype were screen positiveon either parent and/or teacher ASSQ using the 98th percentile,corresponding to a teacher ASSQ above 15 pointsand a parent ASSQ score above 18 points. ROC analysisindicated that the ASSQ worked very well, with high AUCfor both parents and teachers, and especially when combiningthe two informants. The optimal cut-off indicatedfrom the ROC curve was C17 on either parent or teacherquestionnaire, corresponding to an estimated sensitivity of0.91 and specificity 0.86.http://www.springerlink.com.resources.library.brandeis.edu/content/h75m6n6514562833/fulltext.pdf

So, it says what percentage of autistic children scored high on the ASSQ, but not what percentage of children who scored high got diagnosed as autistic.

Finland:

An epidemiological study of 5,484 eight-year-old children in Finland, 4,422 (80.6%) of whom rated on the high-functioning Autism Spectrum Screening Questionnaire by parents and/or teacherhttp://www.ncbi.nlm.nih.gov/pubmed/17450055?ordinalpos=2&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum

With most of these kids rating on the ASSQ for high-functioning autism, it would make sense that a relatively high number would have Aspergers.

For the other Finland Study:The age specific incidence obtained in this study showed the cumulative incidence to be lowest, 6.1 per 10,000, in the oldest age group of 15- to 18-year-old children, and highest, 20.7 per 10,000

So overall, the ratio is one in 800. Contemporary US numbers suggest 1 in 67 in the youngest age group are autistic.

The data from Goteborg overwhelmingly studied children before thimerosal was removed in 1992. Prevalence of children born since then could be completely different. For example, autism in Denmark peaked at 1 in 500 among 5-9 year olds in 1992 but then dropped in that same age group in 2002 to 1 in 1500. http://www.safeminds.org/research/docs/Hviid_et_alJAMA-SafeMindsAnalysis.pdf

Furthermore, one acknowledged limitation about this study being done in Gothenburg:"It might also be argued that the high Go¨teborgprevalence could be due to parents of children withASD moving into the area to avail themselves of betterservices."p. 434

Note: A (very important) reader has sent me a copy of Posserud et al. (2009) - the Norwegian screening of 7-9 year old children.

This is a study that attempts to determine the validity of the ASSQ, not a prevalence study. But we can come up with an estimate.

The total population is 9430, but only 6609 are eligible for the second phase.

Of these, 212 score above cut-off. For various reasons, such as parents not coming back for follow-ups, only 48 children are interviewed with the DISCO. Of these, 12 are diagnosed with an ASD. An additional 2 screen-negative children are also diagnosed.

Now, assuming there's no selection bias (and they do perform an analysis in the paper to try to determine this, and find there probably wasn't) if all 212 children had been interviewed with the DISCO, you might expect 53 of them to have been diagnosed with an ASD.

The ASSQ apparently missed 2 of 14 ASD children. (This is a minimum, as they obviously didn't interview all screen-negative children.) So let's say it misses 14% of all ASD children.

Thus, instead of 53 ASD children total, we should expect to have 60 ASD children total.

We divide 60 by the eligible population, 6609, and we end up with a prevalence estimate of 90.8 in 10,000.

Seems that Jake hasn't a clue about the study that looked into the cultural aspects of what is seen as an issue to be scored on the ASSQ. I know members of the team who did the Finnish study/ies to which he refers (I finished off my BA-equivalence at the university where they work, albeit in a different faculty).

According to Moilanen, Wang, Wang Ebeling, Mattila and Kielinen (International Journal of Circumpolar Health, Vol. 60:2001, Supplement 1):--------------------------------Inter-cultural differences in the Asperger Syndrome Screening QuestionnaireObjectivesThe objective was to study the suitability of the ASSQ in two different cultures.

MethodsThe English version of the ASSQ was translated by PW, a native Chinese infant educator, who has now worked 10 years in the USA. The ASSQ was filled in by the parents of 57 randomly selected Chinese children, aged 5 to 9 years, and by parents and teachers of 101 Finnish children aged 8 years.

ResultsSome questions in the ASSQ, originally developed in Scandinavia, were found not to be relevant in the Chinese context. Chinese children were scored higher, when compared compared with the evaluations of Finnish teachers and of Finnish parents.

ConclusionsBecause of inter-cultural differences , much work is needed to develop Scandinavian questionnaires to be suitable in Eastern countries.--------------------------------

I would say that there are cultural issues also in the way in which the behavioural characteristics upon which Asperger syndrome is diagnosed are perceived by those rating the child's behaviour, and these issues will have some bearing and impact on diagnosis. I was able to see the poster session for this study and a lot of issues of this nature came up in what the poster presentation contained.

This is one of the few good studies being done in Finland at that time (2001, when Finnish research was not as good as it has started to become). The authors of the poster presentation were invited to submit a full paper based on the study, for publication in the actual journal in its next issue. The journal is published by the Institute of Arctic Medicine at the University of Oulu.

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I am the parent of a classically autistic boy, and I'm on the spectrum myself. The science of autism is my main area of interest, but I have a general interest in science and data analysis. My formal training is in Computer Science.

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